Filtering Methodology of Adaptive Median Filter

In this context, the filtering approach of adaptive median filters shares the fundamental principle with conventional median filters - both utilize a rectangular window region Sxy. However, the adaptive variant introduces dynamic window resizing capability where the filter dimensions are modified (specifically expanded) according to predetermined criteria during the filtering process. Algorithmically, this involves implementing a multi-stage validation mechanism: first checking if the current pixel is impulse noise by comparing it against local statistics, then progressively expanding the window until either a valid median is found or maximum window size is reached. Crucially, when the center pixel of the filtering window is determined to be noise through statistical analysis, it gets substituted with the computed median value; conversely, non-noise pixels retain their original values. The final output of this adaptive process replaces the pixel value at coordinates (x,y), which represents the center position of the current filtering window. This methodology significantly enhances noise suppression effectiveness while preserving image details, ultimately improving overall image quality through intelligent, context-aware processing.